The thin slab continuous casting lines of iron mills have a heating furnace of the tunnel type disposed between casting equipment and rolling equipment. The heating furnace has inside thereof a large number of tire rollers arranged longitudinally thereof for transporting slabs as cast.
FIG. 9 shows such a slab transport tire roller 1 which comprises a pipe 4 disposed inside a heating furnace 2 and tires 6 arranged respectively on outer peripheral portions of the pipe 4. The tire roller 1 is rotated by a rotary mechanism (not shown) to transport a cast slab 8 as supported on the tires 6 to rolling equipment through a heating furnace 2 having a high temperature of at least about 1000.degree. C. Accordingly, the tires 6 are made of a material excellent in abrasion resistance and oxidation resistance at high temperatures. The pipe 4 is adapted to pass cooling water therethrough, covered with a heat-insulating material 5 over the portions thereof between the tires and thereby prevented from deflecting or deforming owing to heating.
The tire roller 1 is produced by fitting tires 6 around a pipe 4, fixing the tires to the pipe as by welding, thereafter providing a large number of Y-shaped studs 9 on the outer periphery of the pipe 4, applying a castable or like heat-insulating material 5 to the pipe outer periphery from around the arrangement of studs 9 to such a thickness that the resulting layer is slightly smaller than the tires 6 in outside diameter, and allowing the material 5 to stand for drying.
In fabricating the tire roller of the above construction, the heat-insulating material is not applicable before the Y-shaped studs are attached to the pipe with the tires mounted thereon. Since the heat-insulating material must be dried after the tire roller has been assembled, the roller has the drawback of necessitating a wide space for the drying.
Further because the heat-insulating material is left exposed as it is within the heating furnace, the material is likely to develop cracks due to contact with slabs or slab scale. Such cracks will be further developed as by a centrifugal force during the rotation of the roller, causing the material to separate or fall off. This results in an impaired heat-insulating effect on the pipe, possibly permitting deflection or deformation of the pipe.
It appears possible to protect the heat-insulating material by enclosing the material with a steel plate or the like after the tire roller has been assembled. However, it is impossible to make a tube from the steel plate and fit the tube around the material since the layer of the material formed is given a smaller outside diameter than the tires so as not to contact slabs.
It appears also feasible to wind a steel sheet around the heat-insulating material, whereas it is difficult to fix the steel sheet to the material which is brittle. It is undesirable to fix the steel sheet to the tires as by welding because the sheet is likely to deform when expanded by heating.
An object of the present invention is to provide a slab transport tire roller which is easy to assemble and wherein a heat-insulating material is protected to render the roller reliably operable over a prolonged period of time.